You can use thin provision.Only difference is thin provision uses the storage space on the fly.
Whereas thick will allocate the space in a single shot.
Thin provisioning myth-busters: The benefits of thin virtual disks
This link will guide you.
-SatyS
If you find this useful,please mark the answer as correct/helpful
Regards,
SatyS
http://myvirtuallearning.wordpress.com/
